From: Matthieu Baerts (NGI0) Date: Tue, 5 May 2026 15:00:52 +0000 (+0200) Subject: mptcp: pm: ADD_ADDR rtx: always decrease sk refcount X-Git-Tag: v7.1-rc3~26^2~11^2~7 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9634cb35af17019baec21ca648516ce376fa10e6;p=thirdparty%2Fkernel%2Flinux.git mptcp: pm: ADD_ADDR rtx: always decrease sk refcount When an ADD_ADDR is retransmitted, the sk is held in sk_reset_timer(). It should then be released in all cases at the end. Some (unlikely) checks were returning directly instead of calling sock_put() to decrease the refcount. Jump to a new 'exit' label to call __sock_put() (which will become sock_put() in the next commit) to fix this potential leak. While at it, drop the '!msk' check which cannot happen because it is never reset, and explicitly mark the remaining one as "unlikely". Fixes: 00cfd77b9063 ("mptcp: retransmit ADD_ADDR when timeout") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260505-net-mptcp-pm-fixes-7-1-rc3-v1-4-fca8091060a4@kernel.org Signed-off-by: Jakub Kicinski --- diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c index 3912128d9b86..2a01bf1b5bfd 100644 --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -331,11 +331,8 @@ static void mptcp_pm_add_timer(struct timer_list *timer) pr_debug("msk=%p\n", msk); - if (!msk) - return; - - if (inet_sk_state_load(sk) == TCP_CLOSE) - return; + if (unlikely(inet_sk_state_load(sk) == TCP_CLOSE)) + goto exit; bh_lock_sock(sk); if (sock_owned_by_user(sk)) { @@ -373,6 +370,7 @@ static void mptcp_pm_add_timer(struct timer_list *timer) out: bh_unlock_sock(sk); +exit: __sock_put(sk); }